Comparison of the scope of true and integrated bipolar leads in implantable cardioverter defibrillators

Lead design is a critical factor for detecting and redetecting lethal arrhythmias in electrograms (EGM) from Implantable Cardioverter Defibrillators (ICD). The estimation of the scope of a lead can help to elucidate the anatomical origin of recorded EGM and explain signal features. In this paper, we compare quantitatively the scope of true and integrated bipolar sensing leads by combining bioelectric signal modeling and numerical analysis. We define the scope in terms of the Mean Square Difference (MSD) between the EGM generated by the whole ventricular myocardium and the EGM generated by smaller regions within the ventricular myocardium. Results show that integrated bipolar leads have a wider scope than true bipolar leads, although narrower than unipolar leads. Further, the extent of myocardium within the scope is distributed for integrated bipolar leads along the septum and anteriorly, while for true bipolar leads is located close to the electrode site.